Thermally insulated windows and similar panel structures have been disclosed in the prior art. For example, in U.S. Pat. No. 4,151,642 (Schmidt) a thermally insulated window or door assembly is provided with a centered rigid plastic to provide a thermal barrier between and to connect an interior frame member with an exterior frame member. In this patent, the double glazed window is supported by a single frame. Another type of thermally insulated window or similar supporting structure is disclosed in U.S. Pat. No. 3,686,795 (LaBarge). In this patent, an outer frame member supporting the glass is thermally insulated from the inner frame member and is movable relative thereto. The glass is supported on a plurality of setting or spacing blocks to insulate the glass from the frame.